Abstract: Based on the survey data of 1413 enterprises in Suzhou, we use the propensity score matching method (PSM) to analysis the distribution tendency of government's science and technology projects and the incentive effect on enterprises' R&D input. We consider the internal interaction between government's different R&D supporting methods. This paper finds that government's science and technology projects tend to support enterprises that have high-tech recognitions, stronger investments in R&D and better technical bases. Scientific and technological projects have a significant incentive effect on enterprises' R&D input. These enterprises' average R&D intensity is 3.75 percentage points higher than that of the enterprises that have not participated. This incentive effect is influenced by factors such as high-tech recognition. In the enterprises which have obtained high-tech recognition, the government science and technology projects have a significant positive incentive effect on enterprises' R&D input. This incentive effect is not significant in the enterprises without high-tech recognition.